Synonym of Inadvertent isAccidental, carefree,Careless,Casual,heedless, inattentive,indifferent, involuntary,negligent, nonchalant, off-hand, off-handed,thoughtless, unconsidered,unintentional,unmindful,unobservant,unplanned, unpremeditated,unthinking, unvigilant, unwatchful, unwitting. ...